"""Конфигурация — pydantic models + YAML loader.

Структура YAML:
  broker:
    host: localhost
    port: 1883
    username_env: MQTT_USERNAME
    password_env: MQTT_PASSWORD

  instances:
    - name: livingroom_tv
      zmq_endpoint: tcp://127.0.0.1:5555
      default_layout: quad

  ha_discovery:
    enabled: true
    prefix: homeassistant
    device_name: "CUDA Grid Composer"

  http:
    host: 0.0.0.0
    port: 8080

  log:
    level: INFO
"""

from __future__ import annotations

import os
from pathlib import Path
from typing import Self

import yaml
from pydantic import BaseModel, Field, field_validator


class BrokerCfg(BaseModel):
    host: str = "localhost"
    port: int = 1883
    client_id: str = "cuda-grid-controller"
    username_env: str | None = None
    password_env: str | None = None
    keepalive_sec: int = 30

    @property
    def username(self) -> str | None:
        return os.environ.get(self.username_env) if self.username_env else None

    @property
    def password(self) -> str | None:
        return os.environ.get(self.password_env) if self.password_env else None


class InstanceCfg(BaseModel):
    """Один FFmpeg pipeline = одна cuda_grid filter instance."""

    name: str = Field(description="уникальное имя — становится частью HA entity ID")
    zmq_endpoint: str = Field(
        description="ZMQ endpoint FFmpeg's zmq filter (tcp://host:port)"
    )
    default_layout: str = "quad"
    filter_target: str = Field(
        default="Parsed_cuda_grid_0",
        description="Filter target name в FFmpeg filter graph (для process_command)",
    )

    @field_validator("name")
    @classmethod
    def name_alnum(cls, v: str) -> str:
        if not v.replace("_", "").isalnum():
            raise ValueError(f"instance name '{v}' must be alphanumeric + underscore")
        return v


class HaDiscoveryCfg(BaseModel):
    enabled: bool = True
    prefix: str = "homeassistant"
    device_name: str = "CUDA Grid Composer"
    device_identifier: str = "cuda_grid_controller"


class HttpCfg(BaseModel):
    host: str = "0.0.0.0"
    port: int = 8080


class LogCfg(BaseModel):
    level: str = "INFO"


class Config(BaseModel):
    broker: BrokerCfg = BrokerCfg()
    instances: list[InstanceCfg] = []
    ha_discovery: HaDiscoveryCfg = HaDiscoveryCfg()
    http: HttpCfg = HttpCfg()
    log: LogCfg = LogCfg()

    @classmethod
    def from_yaml(cls, path: Path | str) -> Self:
        with open(path) as f:
            data = yaml.safe_load(f) or {}
        return cls.model_validate(data)